Project Summary
Dorset Council completed an initial review of council depots, creating Heat Decarbonisation Plans (HDPs) for 21 sites. This led to an in-depth study on the site identified as the largest decarbonisation opportunity, with aims to take the outline HDP findings to RIBA Stage 2 and then viable options on to RIBA Stage 3+.
The project was halted at the end of Stage 2, due to cost estimates, lack of business case and availability of external funding. The case study below details the lessons learned.
Our Role
The study was part-funded by the South West Net Zero Hub through our Local Net Zero Fund. The Hub also acted as a critical friend, providing advice on contractor engagement and reviews of work throughout the project.
Technology
Various technologies were considered, including solar PV, air source heat pumps, and battery storage.
Results
The following outcomes were achieved during the project:
Procured a consultant to conduct an options assessment for low-carbon heat solutions on a depot site.
Completed a feasibility study (RIBA Stage 1–2) for low carbon heat technologies, including:
- Site constraints and energy demand mapping
- Dynamic Energy Modelling and CFD analysis
- Solar PV and BESS appraisal
- Lifecycle cycle cost analysis
- DNO engagement
- Heating systems options appraisal including heat loss calculations
Developed a clearer understanding of the challenges and opportunities associated with depot decarbonisation.
The feasibility study has provided valuable insights into the unique characteristics of depot buildings and the opportunities for carbon savings.
Challenges
- Project management: There were multiple project managers throughout the course of the project. This lack of continuity of ownership of the project introduced difficulties with managing the consultants and limited the extent of understanding of technical and financial issues within the project team.
- Contractor engagement: Initial reports from the consultants lacked clarity and were too technical without a clear summary. The council team held multiple meetings to refine the outputs and ensure they were suitable for wider audiences.
- Financial viability: The largest challenge is the general lack of financial viability of converting hard-to-heat buildings with complex use patterns to low-carbon heating projects. It was, however, this very challenge which motivated the study in the first place.
- Closure of PSDS: The closure of the Public Sector Decarbonisation Scheme significantly impacted the council’s ability to fund large-scale capital projects. This emerged mid-project and forced the council to reconsider their financial strategy.
Lessons Learned
- Depot buildings are inherently difficult to decarbonise due to their size, draughtiness and complex use patterns. Early on in the process of creating a decarbonisation plan, the project team should review the building fabric and make a decision on whether it is worth further exploration into replacing the heating system should not be considered if there is poor insulation and airtightness, as this is very unlikely to be cost effective.
- Decarbonisation projects need skilled project management. Upskilling of staff and clearly defined roles and responsibilities are critical for the success of projects such as this.
- Structured engagement with contractors is essential to avoid delays and misalignment. Early and frequent meetings with report authors can save time and improve outcomes.
- Ensure that the Scope of Works includes an Options Appraisal or budgetary insight on Capital Expenditure, Operational Expenditure and Replacement Expenditure. Scope of Works should also consider a Sub Metering Strategy – you can’t manage what you can’t measure.
- The contracted consultants should host a workshop with the supplier, local authority, site users, and any other relevant stakeholders early on in the feasibility study process to focus the direction of the work.
- Limited climate budget funds should be focussed on sites and measures where emissions reductions can be achieved at a better value for money (£’s invested per tonne of emission reduced) and/ or that pay for themselves; just because a site has large emissions, it should not necessarily be the focus of lots of attention and time.
- Given the often long payback period for heat decarbonisation measures, opportunities to generate income could be explored to help raise capital for such measures. This may mean that easy wins (e.g.
,LED lighting or solar panels) are prioritised.
Next Steps
The findings showed that modelling of energy flows in such buildings (with low levels of insulation and high levels of draughtiness) is prone to uncertainty. Measures that significantly reduces carbon footprint would also significantly increase running costs and involving capital spend beyond what Dorset Council can currently afford.
The Council is reviewing the outcomes of the Stage 2 report and considering whether there is a business case for measures such as fabric improvements and more detailed metering. They are also reviewing the council structure and how future large scale sustainability projects can be delivered.
If you work for a public sector organisation and would like to know more about this project, please let us know at SWNetZeroHub@westofengland-ca.gov.uk. Local authorities can also find examples of best practice and similar “leaky building” solutions on Net Zero Go.